Adherence to HIV treatment recommendations including adherence to antiretroviral therapy (ART) and HIV care visits is essential for persons living with HIV to achieve health, longevity, and an undetectable viral load. Some studies have found that women have worse adherence to ART and higher morbidity and mortality than men. Compared to White women, women of color are at higher risk of acquiring HIV, and have worse health outcomes once infected. Thus, there is an urgent need to identify barriers to adherence and associated clinical outcomes among women living with HIV, particularly among minority women, and to develop responsive interventions. One potentially important barrier is HIV-related stigma. Cross-sectional and qualitative studies suggest that stigma and discrimination not only threaten quality of life for persons living with HIV, but are alo associated with worse ART and visit adherence, with negative effects on health outcomes. However, the field has limited understanding of 1) the causal/temporal relationships between stigma, adherence, and health outcomes, 2) the dimensions of HIV-related stigma that influence these outcomes, 3) the causal mechanisms through which stigma may adversely affect health potentially both through biological mechanisms (e.g., chronic stress processes) and through treatment adherence, and 4) the intersection of HIV-related stigma with other forms of stigma and discrimination due to race/ethnicity, gender, and socio-economic status (SES). To address these gaps in knowledge, we will leverage the resources of the national Women's Interagency HIV Study (WIHS), which has been collecting data on HIV-infected women's treatment adherence, mental health, and immunologic and virologic outcomes for 20 years. HIV-infected women enrolled in WIHS face challenges to adherence, and the barriers appear to be even greater for women being newly recruited into WIHS in the southern United States. In addition to supporting continuation of measures of internalized stigma and disclosure in national WIHS data collection, we propose a yearly supplementary visit at 3 WIHS sites in different parts of the country the Deep South, the Southeast, and California. In these visits we will assess theoretically important dimensions of HIV-related stigma, hypothesized mediating mechanisms, intersectional stigma (due to HIV, race/ethnicity, gender, and SES), and chronic stress responses (hair cortisol levels). We will elucidate the longitudinal associations between internalized HIV-related stigma, adherence to HIV treatment, and corresponding immunologic and virologic outcomes in the national WIHS cohort. We will use data collected at 3 WIHS sites to examine a) the associations of other dimensions of HIV-related stigma with treatment adherence and health outcomes, b) potential mechanisms through which dimensions of HIV-related stigma may adversely affect adherence and health outcomes, and c) the link between intersectional stigma and adherence using mixed methods research. Findings will have important theoretical implications, as well as provide crucial information for policies and programs striving to improve outcomes for women living with HIV.